TY - JOUR
T1 - Magnetization Transfer Magnetic Resonance Imaging Noninvasively Detects Renal Fibrosis in Swine Atherosclerotic Renal Artery Stenosis at 3.0 T
AU - Jiang, Kai
AU - Ferguson, Christopher M.
AU - Woollard, John R.
AU - Zhu, Xiangyang
AU - Lerman, Lilach O.
N1 - Funding Information:
This study was partly supported by National Institutes of Health grants DK104273, DK102325, DK73608, HL123160, and C06-RR018898.
Funding Information:
Received for publication March 10, 2017; and accepted for publication, after revision, April 25, 2017. From the Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN. Conflicts of interest and sources of funding: This study was partly supported by Na-tional Institutes of Health grants DK104273, DK102325, DK73608, HL123160, and C06-RR018898. Supplemental digital contents are available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www.investigativeradiology.com). Correspondence to: Lilach O. Lerman, MD, PhD, Division of Nephrology and Hyper-tension, Mayo Clinic, 200 First St SW, Rochester, MN 55905. E-mail: Lerman. Lilach@mayo.edu. Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0020-9996/17/5211–0686 DOI: 10.1097/RLI.0000000000000390
Publisher Copyright:
© Wolters Kluwer Health, Inc. All rights reserved.
PY - 2017/11/1
Y1 - 2017/11/1
N2 - Objectives: Renal fibrosis is a useful biomarker for diagnosis and evaluation of therapeutic interventions of renal diseases but often requires invasive testing. Magnetization transfer magnetic resonance imaging (MT-MRI), which evaluates the presence of macromolecules, offers a noninvasive tool to probe renal fibrosis in murine renal artery stenosis (RAS) at 16.4 T. In this study, we aimed to identify appropriate imaging parameters for collagen detection at 3.0 T MRI and to test the utility of MT-MRI in measuring renal fibrosis in a swine model of atherosclerotic RAS (ARAS). Materials and Methods: To select the appropriate offset frequency, an MT-MRI study was performed on a phantom containing 0% to 40% collagen I and III with offset frequencies from -1600 to +1600 Hz and other MT parameters empirically set as pulse width at 16 milliseconds and flip angle at 800 degrees. Then selected MT parameters were used in vivo on pigs 12 weeks after sham (n = 8) or RAS (n = 10) surgeries. The ARAS pigs were fed with high-cholesterol diet to induce atherosclerosis. The MT ratio (MTR) was compared with ex vivo renal fibrosis measured using Sirius-red staining. Results: Offset frequencies at 600 and 1000 Hz were selected for collagen detection without direct saturation of free water signal, and subsequently applied in vivo. The ARAS kidneys showed mild cortical and medullary fibrosis by Sirius-red staining. The cortical and medullary MTRs at 600 and 1000 Hz were both increased. Renal fibrosis measured ex vivo showed good linear correlations with MTR at 600 (cortex: Pearson correlation coefficient r = 0.87, P < 0.001; medulla: r = 0.70, P = 0.001) and 1000 Hz (cortex: r = 0.75, P < 0.001; medulla: r = 0.83, P < 0.001). Conclusions: Magnetization transfer magnetic resonance imaging can noninvasively detect renal fibrosis in the stenotic swine kidney at 3.0 T. Therefore, MT-MRI may potentially be clinically applicable and useful for detection and monitoring of renal pathology in subjects with RAS.
AB - Objectives: Renal fibrosis is a useful biomarker for diagnosis and evaluation of therapeutic interventions of renal diseases but often requires invasive testing. Magnetization transfer magnetic resonance imaging (MT-MRI), which evaluates the presence of macromolecules, offers a noninvasive tool to probe renal fibrosis in murine renal artery stenosis (RAS) at 16.4 T. In this study, we aimed to identify appropriate imaging parameters for collagen detection at 3.0 T MRI and to test the utility of MT-MRI in measuring renal fibrosis in a swine model of atherosclerotic RAS (ARAS). Materials and Methods: To select the appropriate offset frequency, an MT-MRI study was performed on a phantom containing 0% to 40% collagen I and III with offset frequencies from -1600 to +1600 Hz and other MT parameters empirically set as pulse width at 16 milliseconds and flip angle at 800 degrees. Then selected MT parameters were used in vivo on pigs 12 weeks after sham (n = 8) or RAS (n = 10) surgeries. The ARAS pigs were fed with high-cholesterol diet to induce atherosclerosis. The MT ratio (MTR) was compared with ex vivo renal fibrosis measured using Sirius-red staining. Results: Offset frequencies at 600 and 1000 Hz were selected for collagen detection without direct saturation of free water signal, and subsequently applied in vivo. The ARAS kidneys showed mild cortical and medullary fibrosis by Sirius-red staining. The cortical and medullary MTRs at 600 and 1000 Hz were both increased. Renal fibrosis measured ex vivo showed good linear correlations with MTR at 600 (cortex: Pearson correlation coefficient r = 0.87, P < 0.001; medulla: r = 0.70, P = 0.001) and 1000 Hz (cortex: r = 0.75, P < 0.001; medulla: r = 0.83, P < 0.001). Conclusions: Magnetization transfer magnetic resonance imaging can noninvasively detect renal fibrosis in the stenotic swine kidney at 3.0 T. Therefore, MT-MRI may potentially be clinically applicable and useful for detection and monitoring of renal pathology in subjects with RAS.
KW - atherosclerotic renal artery stenosis
KW - collagen
KW - kidney segmentation
KW - magnetization transfer magnetic resonance imaging
KW - renal fibrosis
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U2 - 10.1097/RLI.0000000000000390
DO - 10.1097/RLI.0000000000000390
M3 - Article
C2 - 28542095
AN - SCOPUS:85019733995
VL - 52
SP - 686
EP - 692
JO - Investigative Radiology
JF - Investigative Radiology
SN - 0020-9996
IS - 11
ER -